Method for manufacturing curve threaded nuts and means therefor



IETHOD Fon'uAupucTua-me CURVE THREADED NUTS AND- IEANS ranasr'on E.HELIN,

June so, 1931.

Filed Feb. 24, 1928 s Sung-sheet 1 INVENTOR:

S MY 0 W Z 0 km a 9.... B

June 30,1931. .E.HE'L|N, ,8

METHOD FOR IANUP'ACTURING CURVE THREADED NUTS AND IEANS THEREFORFiled'Feb. 24, 1928 3 Sheets-Sheet 2 June 30, 1931. E. HELIN 5 3 "ETHODFOR MANUFACTURING CURVE THREADED NUTS AND [BANS TKEREFOR 7 Filed Feb;24, 1928 3 Sheets-Sheet 3 \NVENTOR; E/is Hc/in' HTTORHEY'S.

Patented June 30, 1931 h 1' FELIS Hanna, or mnmnohmnn; STOCKHOLM, SWDEN} aminimalmeantime"g4; 1e28, Serial No 25fii53jlyan d in swerlenAuguste, 1 15527 I This invention relates toa machine forlcuttingcurvethreaded nuts,"inainly characterized by a cutte'r'which atea'chmoment Works on' a nut blanki at a single spot and moves in arelation to the nut-blank along ascrew-line,

the axis of which'is a curve,"and means for guidingthe cutterand-thenut-blank,

case the guiding 'means'are the simplest pos- 10 sible. But: either theaxis of the said screwe line be'a circle or another curve,' the relativemovement of the nut-blank and the cutter; can be two-fold. 'A screw-lineis known to be generated by a doubleimovement, namely a turning movementround the axis of the screw-line and a longitudinal movement in thedirection; of the said axis, and this latter movement can diflt'er; Ofthe two special cases here referred to, one is characterized by I i sothe turning planeoffthegeneratrix (in this I instance the cutter)ateverymoment'ofthe niovementflbeing at right angles to the,

r curved axis ofthels'crew-line', and-the other by the said plane movingtranslatorily. ZIhe' double movementof the cutter in relation to,

the nut-blankis'in bothfc'ases assumed to take place ini such-a manner,that the cutter performs the turningfmovement and the, nutblank thelongitudinal movement In prac-' so tice the second special case is tobepreferred;

shows a cutterin the form of a milling-wheel.

Figs. 7 and S are diagrams showing adjustment of. the cutter, Fig.9'in'dicatesjthe cutting periods. .Figs. 10 and 11 show a ma chine forformingthe nuti Fig. 12'shows a j form of cutter.'

Ema/inples'of curzedihut'constmctz'on Fig. 1 illustrates 'a procedurefor generat ing a curved thread. A cutter '1 rotates with constantangular -speedv rollhd '3; axis pin at 0; If a'thread has beengeneratedyas nad,' situated.in theqplane, and parallel with axis The nut-blank 2 -movesjalso "with constant angular speed along anarc, having 0as centre, to and past the rotary plane 'g O'of cutter 1; from positionI to position- II in'Fig. 1; The nut-blank of suitablefo'rm,

V v 2, is afiixed to a rod on: line OB, turnable on' The said curve maybe a circle, in which a pin at 0. During the motion of thenutblank-2toward the cutter 1 the latter gener at s a read with a;certain deformation'cor- 6 responding to the guiding of the nut-blank.IfI as shown inFi'gl." Fig.2'showsthe characv 'ter of thedeformationensuing in this case, i

the bending being shownflexaggerated.

' shows a procedure whereby a curved [thread of a difierent charactercan be obtained. Cutter'l rotates, as previously; with a" constant anglespeed round afixedaxi's I aa,'parallel with axis XX', the rotation" alsoin this instance taking place inplan e g0. 0

A nut blank 2 of suitableiform is fixedto a.

translatorily movable rod located at PQ, V

which is guided by another guiding. d, 10-

catedatOP turnable on pins at O and P. jNut bl'ank 2 moves with aconstant linear 9 speed 'along axis XX, its movement being ,translatoryand in "an arc with O as 'centre towards and past the rotary 'cpl'ane 0of cutter 1, from position'I to 'position'II in Fig. 3,. During. the amovement of the. nuts 9 blank 2 toward the cutter 1 th elatteri gencrates a thread with a certain deformation corresponding tothe guidingof thenut ;bla'nk; 2, as shown in-Fig', 3. Fig.4 shows,;

with exaggerated bending the character {of the deformationthus created."For obvious reasons the bending of the'generated'thread will in thiscase be convex in relation tonthe r by themethod shown in Fig.1,fitsbend will naturally be concave in relation to thesarne pin. a

*By using isernguiain mamas ad 4 speeds, curvedthreads of aninfinite'nuinber j" of variations canbe made, and each variation will in"alllinstan'ces correspond toa certain deformation of'the thread It isof course i not essential that the movements; should be a uniform,asassumed above. By changing the 7 speed of the nut-blank furthervariations will 3 be effected. The centre line of the thread canfurthermore be bent in another curve than an arc.

A curved thread cannot be cut to the full depth in one screw-linemovement by using a cutter. The nut-blank, on the other hand, must beoperated by the cutter several times, as a cutter cannot, as a rule,make so deep a cut as a full profile of the thread. Threadcutting with acutter is shown in Fig. 5, while cutting with a milling-wheel is shownin Fig. 6. As for Fig. 6, it may be observed, that the axis of themilling-wheel is notparallel with the axis of the nut-blank, but owingto the pitch of the thread it is inclined to the said axis.

The shape of the nut-blank 2, to be treated as indicated above, is theusual one with outlines as per usual types and with an unthreaded holethrough the centre, the said hole, (as it will be seen from F 2 and at)ought to be of a somewhat smaller diameter than the core-diameter of therespective thread-dimensions.

The shape of cutter 1, which does the work, should suit the threadprofile. The cutter may, however, whenever necessary have, a chamferingedge la (see Fig. 12) to cut the threads-tops to the required heights.

As mentioned previously, a cutter must cutthe nut-blank several timesbefore the profile of the thread is completed. This results in thenecessity after each time to readjust the cutter. This can be doneeither as indicated in Fig. '7, by causing the re-ad'justing movement ofthe cutter to take place in the plane y O or as shown in Fig. 8 bycausing these movements to follow the surface of a cone TUV, thevertical angles of which 2 "e equal to (l-n) 0 when nis the edge angleof the thread. In both instances it is essential that these movements ofthe cutter be gradually decreased from acertain initial magnitude as thethread is nearing its completion in the manner shown in Figs. 7 and 8.In these figures for clcarness sake only a few cuts have been shown asnecessary.

It will be understood from the above, that to cut a thread to its fullprofile, the movement of the cutter relative to the nut-blank, i.- e.the setting, the working and the retiring movements occur in conformitywith a certain series of periods. Such a has 4: single periods combinedin a manner as shown in Fig. 9. In the diagrams of Fig. 9: ithas beensupposed that the cutter is set-on in plane yO. For each cut the cuttermust (a) Be advanced radially (positive movement).

(6) During the cutting operation advance axially (positive movement).This is made possible by the movement of the nut-blank. Compare Figs. 1and 2.

(0) Be returned radially (negative movement).

(d) Return axially when idle (negative movement). This is also done bymoving the nut-blank.

It is obvious that a machine, Working under this scheme, cannot have alarge output, should it not be an automatic one, i. e. the said periodsshould follow each other automatically, and the series of periods adalso to be automatically repeated as many times as required forcompletion of the thread.

An automatic thread-cutting machine for the manufacture of the nuts inquestion can be divided into two parts, one of which refers to themanoeuvring of the cutter, and the other one to the manoeuvring of thenut-blank.

he machine, which will now be described, is for the nut-blankillustrated in Fig. 3. I

From what has been mentioned above it is evident that the movement ofthe cutter relatively to the nut-blank is composed of a. r0- tary and atranslatory movement. As indicated in Fig. 3, the components of thesemovements are realized in the threadcutting machine (automatic) so thatthe cutter has a rotary movement only and the nut-blank a translatorymovement only. As the nut blank must be out several times by the samecutter or tool before a thread of required depth is produced, themachine is provided 'ith return movements, contrary to the workingmovements, whichmay be referred to as positive. In this instance, theadvance translatory movement of the nut-blank can be followed, withadvantage by a negative back-movement, the rotary movement of the cuttershould however, not be altered. From a constructional point of view itis decidedly of advantage to cause the rotary movement uninterruptedlyto continue even during the movement of the blank. To enable-this to bedone, both the return and positive movements of the cutter take place ina radial direction, of which otherwise only the latter would have beenneeded.

When the above method is followed, the movement of the cutter ischaracterizedby a positive advance movement of the magnitude a1 (seeFig. 7) then a period of rest; then a back-movement of the samemagnitude as the advance movement; and then a period of rest. This isfollowed by the positive a2; rest; a return movement as large as a2; arest. After this follows a positive movement a3; a rest; a returnmovement as large as a3; a rest, etc.

For the proportions between a1, a2, (43, etc. applies that :al a2 a3etc.

Finally, from what has been explained previously :a2a1 a3a2 a4la3 etc.

Seen from a purely mechanical point of view a maneuvering device for thecutter may be arranged in the following manner (see Figs. 10 and 11) atright angles to the rotary axis aa, as shown in Fig. 7. A modificaill! 'tion with an: advance as shown vini'F-ig. 8'is not quite so simple;though-it, does notoffer a any constructionalidifiiculties. "The cutterllis. fitted in holder 3,=which can be; moved diametrically ina chuckmounted on the drivingshaft'5 (a a). The holder 3 is movable on guide 6andit-s diametral movements are caused by screw'Z.) Idle movementbetween holder 3 and screw 7 isleliminate'cl'by springs 8. The's crew 7is provided w ith a gear Wheel 9 meshing with two gears, ,12and 13respectively on axes and .11. On these latter axes striking armsl4-and15 arefixed which I project outside chuck 4 through apertures inits cylindrical wall. {By means of springs (not 'shown onthe drawings)thestrikingf armsl and; are kept in their normal position of rest andpressediagainst the fore edge of the apertures in chuck 4. Thestrikingresulting in cutter -1 movingdiametrically v armslet and 15 carry' pawls-17 actuated by springs 16, these. pawls being held in a. position ofrelease; when thestriking arms 14 and 15 are in a position of rest-bypressure against the edges of the apertures in the chuck k When eitherof these arms isturned the pawls 17 engagedwith ratchet wheels18'fixedto axes 10 and 11; so that'the corresponding axes 10 and 11partake in the turning movement, which is then by the gear wheel9transferred to screw 7. It will be seen, that to'turnthe striking arms14 and 15 in thesame direction,

the screw 7 will turn in different directions,

in different directions inchuck The cutter .1 can consequently bemanoeuvred' by alternatively'acting. and suitably arranged obstructionplaced in the wayof the'striking v I arms '14; and 15, when chuck4 isrotating.- -V

Should such an'obstruction as20 (see Fig;

10) be'placed in the way of the striking arm 15, the result will be thatwhen chuck 4: rotates thestriking arm will swing'from this hindrance fora certain angle w,- whosemag nitude will depend upon the rise (H), withwhich the hindrance 20 enters into the field of rotation of striking arm15. I .By varying this rise H and consequently the angle of w the degreeof the radial removal'of cutter 1 per turn of the rotation of'-'chuck 1may" also be varied. v i j As mentioned above g one "ofj thestrikingarms 14 and 15 regulatesthe advance and the other one the returnmovementof the cutter.

From Fig. 11 it will ,beseengthat the striking.

arm'14 is supposedto bring about the advance, and the striking arm 15thereturn movementofthe cutter. The alternatively acting obstructionstriking arm 14 and 15 have been formed as a' kind of toothed discs 19and 20 which, by twofiv'orm gears, 21 and 22 respectively areconnected'with'a coinmon driving shaft-23; The toothed di'scs 19 and' 20are constructed in such manner that the width of the teeth is on-lyhalfthe'width of the interstices; If the division is wP,'-a-tooth comprisesa central angle erec /3, and the V intersticef a central angle 12w/3.Initially these toothed discs 19and 20 are set'alternat- -ing,- so thatthe back-disc 20 has an advance angle-ofw/3Qin the direction of therotation. The turning movement of toothed discs Thegdiscs 'con- 19 and20,; is intermittent. sequently moverintermittently, butsimultaneously,fand the angle movementisgeach time of the magnitu'de109/3. Thus the strik- 'jing'arms 141 and 15] are actuated in; the:fol-" lowing'manner. In the position occupied by t 1 toothed' discs19'and 20 ,in'Fig. 9;, the strik ving arm ,l, forthe movenientofadvanceis v a while .striklng arm 15 for the return 'move- I iment 1spasslng thrfoughan interstice in dlsc 1 about tostrikeagainst a tooth:in disc;19,-

20, This state ismaintained during m revolutions of chuck 1, duringwhich the total setting-on will reach or (seeFig; 9) After m revolutionsof chuck 4, discs 19 and20 advance one step or anangle of w/3. In thistheir second combination both the of positions the striking; arm 14 hasentered aninterstice of disc 19. The striking arm 15 is stillin the sameintersticev of disc 20. At a this stage it must be borne in mind that"the. width or the interstices is double the" 'ioo After it revolutions of'chuck'4c,' the toothedj.

discs 19 and 20 advance another step of the i I same magnitude, viz; 10/3. In the third combinations of positions thus, arrivedat,'

strikinglarm.1 1, in analogy with whathas been said wlth reference tostriking arm 15,. remains in an interstlce Of CllSG 19. The

striking arm representing the back movement, 15, on the contrary hascome 'incontact with a tooth on-di'sc 20. i This state continues duringlm, revolutions of chuck- 1,; during which period'the total returnmovement will reachxthe magnitude 0 (see 9); It has. previously'mbeenpointed out that the, for

ward an d backanovementfs are equal during one single period;

1 After m revolutions "chuck 4 the two discs'l9 and 20. advancefurthero-ne step to I the same extent as-before, viz i w /3, and in sodoing occupy a fourth combination of position, when obviously strikingarms 1ft and'15 have entered the interstices of the 'respective-tootheddiscs 19 and'20, and'thus are in rest as-regards rotating chuck 1. Thiscondition continues during a revolutions, 1

when cutter 1 performs its return'periodd' see F ig; 9) on thenut-lolankbeing returned, the procedure of which-is explainedbelowv 5'"Now; one series of periods for instance (Z1dl, is completed. The newa2d2, which immediately follows is similar in every respect to theprevious one, apart from the fact that a2 should be of greater valuethan al, and consequently also 02 of greater value than 01. As mentionedpreviously a and a should increase at each series of periods until thethread is finished. This is attained by the said discs 19 and being ofspiral shape so that a subsequent tooth (in the direction of rotation ofthe discs) has a larger radial extension than the previous one. Theradial extension of the teeth should consequently be calculated first,with regard to the general rules for the magnitude of a1, a2, (43, etc.as mentioned above with reference to the operation of the cutter(compare Figs. 7 and 8), and then with regard to practical circumstances(such as conditions to be taken into consideration with regard to thecutter etc). Finally it may be pointed out, that the number of teethshould be equal to the necessary number of series of periods for cuttingcertain thread dimension.

Different constructions of the toothed discs should consequently beused. for different thread dimensions. For the intermittent feeding ofdiscs 19 and 20 the following gearing means may be used. On the commondriving shaft 93 of discs 19 and 20 a toothed wheel 2a. On anindependent shaft a toothed wheel 26 is. mounted. This latter wheel isprovided with two teeth 2?, which are placed apart in such manner thatthe angle distance is in the relation of own. The above mentioned shaft25 is set in motion by the driving shaft 5 by means of gearing, 28 orthe like, in such proportion that when shaft has completed onerevolution,

. the shaft has turned in plus 91 revolutions.

In consequence of the arrangement described above the toothed discs 19and 20 will advance one step (w /S), alternatively after every m andevery a revolution of driving shaft To operate the nut-blank thefollowing arrziuigen'ients are provided.

The stand 29 of the machine constructed with a guide 30 parallel withthe rotary axis (ca) of the cutter. Along with this guide 30 there is amovable support 31. Support 31 is constructed with a guide 32, runningat right angles to the said (6--C6. Along with guide is a second movablesupport 33, carrying a chuck 3 for nut-blank 2.

The longitudinal support 31 has an oscil lating movement, theoscillations being suit-- ably interrupted with periods of rest, whichare so arranged that they agree with the advance and return periods aand c respeetively (see Fig. 9) of cutter 1. This oscilla ing movementis suitably imparted to support 81 from a cam disc 35, which derives itsrotation through suitable transmission arrangements from shaft 5, seeFig. 11, the ratio of the longitudinal support 31.

of transmission being such that the cam disc 35 makes one revolutionduring each complete operation of the nut-blank 2 and the cutter 1.Support 31 cooperates with a return-spring 36 in such manner, that themovement during the working period b of the cutter (see Fig. 9) isdirectly caused by a cam disc 85. whereas the movement during the periodof return (1, is caused by the said spring 36. The periods of rest ofsupport 31 correspond on the cam disc 35 with circle-sectors.

The transverse support 33 receives its motion from the longitudinalsupport 31 by a guiding arrangement consisting of a roller or the like3'? fitted to support 33, which roller by a spring 88 acting on support33-is held pressed against a curve-segment 39 in the stand 29, whichsegment will then act as a guide for the component of the translatorymovement at right angles to the axis of rotation (rt-00). The othercomponent of the translatory movement parallel with the said axis (aa)is identical with the movement The curve segment 39 may be of any form,but is on the drawing shown as circular, the described arrangementthusacting similarly to the ar rangement, which is shown schematically inFig. 3.

Having now described my invention, what I claim as new and desire tosecure by Let ters Patent is z 1. A method of cutting a curved threadednut from an apertured nut-blank by means of a cutting member inengagement with the bore of said nutblank, consisting in rotating saidcutting member and simultaneously imparting to one of said members atranslatory movement corresponding to the desired curve of the thread.

2. A method of cutting a curved threaded nut from an apertured nut-blankby means of a cutting member in engagement with the bore of saidnut-blank, consisting in rotating said cutting member and simultaneouslyimparting to said nut-blank a translator-y movement corresponding to thedesired curve of the thread.

3. A method of cutting a curved threaded nut from an apertured nut-blankby means of a cutting member in engagement with the bore of saidnut-blank, consisting in imparting to one of said members a movementparallel to itself along a curve corresponding to the desired curve ofthe thread and simultaneously rotating one of said members.

4. A method of cutting a curved threaded nut from an apertured nut-blankby means of a cutter in engagement with the bore of said nut-blank,consisting in rotating said cutter, simultaneously imparting to saidnut-blank a movement parallel to itself along a curve corresponding tothe desired curve of the thread and repeating said operations, untilcutter,simultaneouslyimparting to saidnutcorresponding to the desiredcurve of the v rotation. V v

the desired depth of the profile of the thread is obtained. i a

5. A method of cutting a curved threaded nut from an apertured nut-blankby means of a cutter in engagement with 'the'bore of said nut-blank,consistingin rotating said,

blank a. translatory movement along acurve thread and 'repeating'saidoperations, until the desired depth of the profile of thethread isobtained, while maintaining the cutter in 6. A method of cut-tingacurved threaded 5 nut from an apertured nut-blank by means? of a cutterin engagement with'the boreof said nut-blank, consistingin rotating'saidcutter and simultaneouslyimpartingto said nut-blank a movement parallelto itself along a curve corresponding to' the desired curve of thethread, adjusting the cutter j' radially outwardlyin relation to thenut-p blank and repeating the operations, re-adjusting the cutterradially inwardly in relation to the nut-blank and repeatingtheadjustment and rotation of the cutter as vwell as the movement of thenut-blank, until the f a desired depth of the thread is obtained, -7. Amethod of cutting a curved threaded *nut from an apertured nut-blank bymeans of a cutter in engagement with thebore of said nut-blank,consisting in rotating the cutter, ,moving the nut-blank parallel toitself along a curve corresponding to the desired curve of the thread,adjusting the cutter outwardly. in relation to thenut-blank V andrepeating the operations, re-adjusting the cutter inwardly in'relationto thef nut; blank, repeating the adjustment and rotation of the cutteras well as'themovement of the nut-blank, until the desired depth of theprofile of the thread is obtained, while controlling the-adjusting'andre adjusting "movement of the cutter insuch manner that r the differencebetween two consecutive adjustments becomes smaller from stage to stage.v a r v machine forcutting curved threaded nuts. from aperturednut-blanks comprising a a cutting member, means to-rotate said cut- St-A ting member, a support for said nut-blank nuts from aperturednut-blanks, compris ing a cutter,means'to rotate said cutter, a

support 'for'thenut-blank, means to move I I said support parallel toitself along a curve corresponding to the desired curve of the thread tocause the cutter tooperate on the bore of the nut-blank, means-to adjustthe cutter radiallyin relation to the bore of the I nut-blank, saidlast-mentioned means being,

adapted to vary said radial adjustment of the cutter," i

ontheholder engaged by'the screw to recip- "rocate the holder, a gear onthe screw, a pair of gears mounted in the chuck engaging said I Y 7gears on opposite sidesto turn the screwya shaft for eachgsai'd twolatter gears, a'ratchet wheel on each said shaft, an arm projecting 11.A machine for cutting curved threaded I I a nuts, comprising avchuckmounted torotate .a holder for the cutter mountedin the chuck, va cuttersecured to the holder,a screw'shaft v a y in the chuck arranged toturn,- a nut portlon' I from thechuck that turns on; each said twoshafts, a pawl oneach said arma'rranged to I 1 engage said ratchet:whe'els respectively, a "toothed disc for each said pawl arranged toengage the pawl intermittently by the teeth 7 to cause the pawl toengage the ratchet wheel and turn the said gears. and screw and shiftthe holder andlcutter, means forrotating the chuck, means 1 for turningthe. tooth discs F and cause them to alternately enga e a pawl andswingthe holder in opposite the severalteeth on each disc being arranged to,progressively increase the swinging of the pawl and resulting movementof the screw, and a support for a nut-blank that is directions I shiftedfrom the driving means for the chuck to advance the nut-blank to causeits bore to be engaged by the cutter. 7

12. Machine as set forth in claim 11in movement in which its axis variesin re-] l'ation' to the plane of ter point.

In testimony whereof have" signed nly name. to this specification. 1 a jg ELISHELINJ a cutter, means to rotate said cutter, a support for thenut-blank, means to advance said support translatorily along a curvecorresponding to the desired curve of the thread j to cause the cutterto operate on the bore of I the nut-blank and means toadjust the cutterradially in relation to the bore of the nutblank.

10. A machine for cutting curved threaded I which the nut-blank isgivenan advance V movement of the cut-

